In recent years surgeons have turned more and more to the use of surgical staples, rather than conventional thread sutures, for closing wounds or incisions in the skin or fascia of a patient. This is true, in part, because the stapling operation is a simpler procedure in many instances. More importantly, however, is the fact that the stapling procedure is very much faster than conventional thread suturing. Thus, particularly in those instances where a large number of sutures is required, the length of time for the suturing procedure and the length of time the patient must be maintained under anesthesia are greatly reduced when surgical staples are used.
U.S. Pat. Nos. 3,643,851; 3,717,294; and 3,837,555 illustrate typical surgical staples. A staple of the type shown in these patents initially has an elongated crown terminating in downwardly depending leg portions. The free ends of the downwardly depending leg portions are provided with downwardly and outwardly sloping cuts, forming points. During the forming and implanting of such a staple in the skin or fascia of a patient by a surgical stapling instrument, end portions of the elongated crown are bent downwardly. This results in a staple with a narrower crown and L-shaped legs, the pointed ends of which are opposed, and the L-shaped legs being embedded in the patient's skin or fascia.
Another type of surgical staple is taught in U.S. Pat. No. 4,014,492. This staple initially comprises a central crown portion terminating at either end in portions sloping upwardly and outwardly, these upwardly and outwardly sloping portions, in turn, terminating in downwardly and outwardly sloping portions. The last mentioned portions are provided with cut surfaces forming points. The cut surfaces initially lie in a position substantially perpendicular to the staple crown and the skin or fascia of the patient to be joined. During forming and implanting of this type of staple, the upwardly and outwardly sloping portions of the staple, at their junction with the crown, are bent downwardly to form a staple having a crown and L-shaped legs, the points of which are opposed.
Either type of surgical staple described above can be removed from the skin or fascia of the patient by bending the staple crown into a U-shaped configuration. This will cause the L-shaped legs of the formed staple to shift upwardly and outwardly so that they may be lifted from the patient's skin or fascia.
Prior art workers having developed manual extractors for bending the crown of surgical staples and lifting the staple from the patient's skin. In its typical form, a prior art extractor comprises a pliers-like tool having first and second handle means pivoted together and formed of sheet metal. The first handle means terminates in a pair of anvils in parallel-spaced relationship. The anvils are provided at their rearward ends with notches so that, when the anvils are slipped under the crown portion of a surgical staple, the crown will be received in the notches.
The second handle of the extractor generally is provided with a relatively thick, two-ply, blade-like forward end substantially as long or longer than the anvils. When the handle elements of the extractor are in their open position, this blade lies above the anvils and the notches therein. As the handle elements are shifted to their closed positions, the blade element passes between the anvils and the notches therein making the above described U-shaped bend in the staple crown located in the notches.
In the use of an extractor of this type, the anvils (when slipped beneath the crown of a staple) will rub against traumatized areas of the skin, causing pain to the patient. Since the blade portion of the extractor is as long or longer than the anvils, it partially obscures the anvils, making their proper insertion under the staple crown and location of the staple crown in the anvil notches more difficult. Furthermore, when the extractor anvils are parallel throughout their length, the operator may inadvertently slip only one anvil under the crown of the staple to be extracted. Under these circumstances, the staple will not properly open and if the operator pulls the extractor upwardly the patient will undergo severe pain.
When such a prior art extractor is actuated to bend the crown of a surgical staple, clearance between the blade and the anvils is such that the crown tends to make the anvils spread apart, further irritating the traumatized skin. As a further consequence, the legs of the U-shaped bend in the staple crown are generally non-parallel, with the result that the staple legs themselves are not fully opened. In addition, such extractors are generally constructed in such a way that the first handle element can inadvertently become "flipped" (or pivoted through more than 180.degree.) with respect to the second handle element, thus rendering the extractor useless until its handle elements are returned to their proper orientation. Frequently, such prior art extractors are provided with means to bias the handle elements to their open position. This biasing means can become dislocated, tending to jam the extractor.
U.S. Pat. No. 4,026,520 teaches a manually operated surgical staple extractor of pliers-like form and having first and second handle elements pivotally joined together near their forward ends. These handle elements are manually shiftable between open and closed positions and may be biased to their open position. The biasing means is so configured that it cannot become dislocated and jam the extractor. Furthermore, means are provided to prevent one handle from becoming "flipped" with respect to the other.
The first handle element of the extractor of U.S. Pat. No. 4,026,520 is bifurcated at its forward end, the bifurcations terminating in a pair of elongated anvils in parallel-spaced relationship with the forward ends of these anvils angled toward each other so that the frontmost tips thereof are contiguous or nearly so. At the rearward ends, the anvils are provided with aligned notches to receive the crown of a staple. The bifurcations of the first handle element provide a steep upwardly and rearwardly sloping surface adjacent each of the anvil notches to assist in and ensure the location of the staple crown in the notches.
A thin blade means is located between the bifurcations of the first handle element and is operatively connected to the forward end of the second handle element. The blade means has a nose portion shorter than the anvils and a lower edge adapted to produce a U-shaped bend in the crown of a staple located in the anvil notches. The blade nose portion is shiftable by the second handle element between a first position (when the handle elements are in their open position) wherein the lower edge of the nose lies above the anvils and the notches therein, and a second position (when the handle elements are in their closed position) wherein the nose lies between the anvils with the lower edge of the nose located below the anvils. The anvils are so spaced from each other and the nose of the blade means is sufficiently thin that clearance is provided between the nose and each anvil substantially equal to the diameter of the crown portion of the surgical staple being extracted. As a result, the anvils do not tend to spread during an extracting procedure and the surgical staple legs are fully opened.
U.S. Pat. No. 4,026,520 teaches two embodiments of the extractor. In one embodiment, the blade comprises an integral one-piece part of the second handle element. In the other embodiment, the blade is a separate element pivotally mounted between the bifurcations of the first handle element and operatively connected to the forward end of the second handle element.
While the extractor of U.S. Pat. No. 4,026,520 represents a considerable advance in the art, it still is characterized by certain deficiencies. First of all, the anvil portions are of considerable thickness, causing trauma when slipped beneath the crown of a surgical staple, especially when the staple is embedded. Furthermore, as is true of other prior art extractors, the extractor of U.S. Pat. No. 4,026,520 has a tendency to bend a surgical staple in more than one plane during the extracting procedure, again increasing the trauma experienced by the patient.
The extractor of the present invention is intended to overcome the problems encountered with prior art extractors and to constitute an improvement thereover. Its construction is simple and inexpensive so that, while it may be manufactured as a reusable and resterilizable tool, it lends itself well to being produced in the form of a single-use, disposable tool. The extractor is characterized by a one-piece, horizontal anvil, slightly pointed at its forwardmost end and of minimal thickness to greatly reduce the trauma in placing the anvil under the staple crown. The anvil is provided with means for positive and exact positioning of the staple crown to prevent slipping while reforming the extracting a staple. The reforming of the surgical staple is accomplished substantially in a single plane and in the configuration of the anvil, together with the provision of a thin blade, makes it possible to achieve parallel staple legs during the reforming and extracting process. This enables the legs to be lifted from the skin or fascia of the patient with minimal discomfort. The handle portions are provided with scissors-like, finger-engaging loops designed to lend the extractor stability during the extracting procedure. The handles are provided with stops giving the surgeon a positive tactile feedback when the staple is properly reformed, and insuring that each staple is identically reformed. A novel method of attaching the looped handles to the instrument is taught. Preferably, spring means are provided to bias the handles to their open positions. The spring is so mounted that it cannot be dislocated, and thus cannot jam the extractor. The combination of the blade of the lower handle and the slotted forward end of the upper handle prevent the possibility of one handle becoming "flipped" with respect to the other. A plastic insert takes up the slack between the handle elements at the point at which they are pivoted together, lending a firm and positive scissoring action to the instrument. Finally, while the instrument could be made of materials such that it could be reused and resterilized, it can be manufactured quite inexpensively, lending itself well to being a single-use, disposable instrument. The instrument also lends itself well to appropriate presterile packaging.